The gentleman at the pet store assured me that the yellow canary I had just purchased was a male and as such would delight me with song.
A few weeks later I noticed some odd behaviour of him tearing up pieces of newspaper from the bottom of his cage and putting that paper into his seed bowl. This went on for a few days and then one morning there was a pretty little blue egg. Quite clearly he was not a he but a she!
By the end of that week we had four little motley coloured eggs of the prettiest blue hue.